The coagulation properties of milk supplied by the dairies are of great importance to the cheese industry. Milk with favorable coagulation characteristics, e.g. short coagulation time and high curd firmness, may produce higher cheese yield with a desirable composition as compared to milk with less favorable properties.
In the article “Review of systems for monitoring curd setting during cheesemaking” by O'Callaghan et al., published in the Journal of Dairy Technology, Vol. 55, No. 2, May 2002, pp. 65-74, which is incorporated herein by reference in its entirety, known methods for detecting coagulation properties of milk are described. The methods described are based on physiochemical changes that occur in milk during rennet coagulation. Typically, rennet is added to milk samples extracted from a general collection tank in a dairy and coagulation properties of the coagulating milk are measured.
In the article “A comparison of the methods for determination of the rennet coagulation properties of milk”, by KÜBARSEPP et al, published in Acta Agriculturae Scand Section A, 2005; Vol. 55: pp. 145-148, which is incorporated by reference in its entirety, there is described two known technologies for measuring coagulation properties: the formagraph and the optigraph.
According the article by KÜBARSEPP et al., the formagraph measures tiny forces exerted by a pendulum when samples of coagulating milk are exposed to linear oscillations. The recorded measurements are firmness and time. Firmness is typically defined as a combination of viscosity and elastic characteristics of the coagulating milk.
According the article by KÜBARSEPP et al., the optigraph is based on measuring Near InfraRed (NIR) signal attenuation emitted from the coagulating milk as the coagulation process develops.
Both methods require adding enzyme prior to performing the measurement and are therefore destructive. The analysis duration of these methods may be longer than the milking session and are therefore are implemented for evaluation of the milk at a dairy in the general tank.
International Patent Application Publication WO03040704 entitled “Spectroscopic Fluid Analyzer” which is incorporated herein by reference in its entirety, describes an NIR spectroscopy fluid analyzing system for determining concentrations of component parts of fluid. The system uses a series of Light Emitting Diodes (LEDs) for illuminating a sample of fluid and photo-detectors for measuring the transmission absorbance through the sample and the reflectance or scattering from the sample for the wavelength range of each LED. The concentration of component parts of the sample is expressed in the form of a polynomial which is a function of the measured transmitted and/or reflected intensities, and of empirical coefficients, which are extracted by prior statistical analysis on measured intensities obtained from a large number of test samples having known concentrations of the component. Also described in WO03040704 is a sample chamber capable of being used to perform optical absorption measurements on a flowing sample of fluid.